Hamstring Autograft Versus Hybrid Graft for Anterior Cruciate Ligament Reconstruction: A Systematic Review

Background: Hamstring tendon autografts are commonly used for primary anterior cruciate ligament (ACL) reconstruction. Some patients have small hamstring tendons however, which may compromise the clinical outcome of the autograft. To solve this problem, many surgeons use hybrid grafting that involves augmentation of small hamstring autografts with allograft tissue. Purpose/Hypothesis: The purpose was to compare the clinical outcomes between primary ACL reconstructions performed with hamstring autografts and those performed with hybrid grafts in terms of patient-reported evaluation, failure rate, and knee stability. The hypothesis was that primary ACL reconstruction performed with hamstring autograft alone will not differ significantly from that performed with a hybrid graft in terms of patient-reported evaluation, failure rate, or knee stability. Study Design: Systematic review. Methods: A systematic review was performed to identify prospective and retrospective comparative studies and cohort studies (evidence levels 1-3) comparing outcomes of primary ACL reconstructions performed with hamstring autografting alone and hybrid grafting. Outcomes included patient-reported evaluation, failure rate, and knee stability. Results: Ten studies were included: 1 of level 2 and 9 of level 3. Collectively, they included 398 autografts and 341 hybrid grafts. Mean respective follow-up durations ranged from 24.0 to 69.6 months and from 24.0 to 70.8 months. Patient-reported evaluations, including Lysholm, Tegner, and subjective International Knee Documentation Committee scores, were reported in 8 of 10 studies. Failure rates were reported in all 10 studies. Results of knee stability examinations-including KT-1000 arthrometer measurements, the pivot-shift test, Lachman test, and overall International Knee Documentation Committee results-were reported in 4 of 10 studies. In this review, there were no statistically significant differences between autografts and hybrid grafts in terms of patient-reported evaluations, failure rates, or KT-1000 measurements. Conclusion: In this systematic review, there was no significant difference in patient-reported evaluation or failure rate between primary ACL reconstructions performed with autografts alone and those performed with hybrid grafts. Whether there is a substantial difference in knee stability examination results between autografts and hybrid grafts remains unknown, given a relative lack of reports on knee stability.